/**
 * 城乡桥平台微信后端服务模块
 * 提供微信小程序后端API，包括用户认证、订单管理、商品管理等
 * 与前端微信小程序配合，同时集成DeepSeek AI服务
 */

const express = require('express');
const router = express.Router();
const axios = require('axios');

// 服务配置常量
const WECHAT_SERVICE_CONFIG = {
  // 微信API配置
  wechat: {
    appId: process.env.WECHAT_APP_ID,
    appSecret: process.env.WECHAT_APP_SECRET,
    apiBase: 'https://api.weixin.qq.com'
  },
  // 业务配置
  business: {
    maxProductsPerUser: 100,
    orderTimeout: 30 * 60 * 1000 // 30分钟
  }
};

/**
 * 微信用户控制器
 */
class WechatUserController {
  /**
   * 微信用户登录
   */
  async wechatLogin(req, res) {
    try {
      const { code, userInfo } = req.body;

      // 参数验证
      if (!code) {
        return res.status(400).json({
          error: '参数错误',
          message: '微信登录code不能为空'
        });
      }

      // 1. 通过code获取openid和session_key
      const authResult = await axios.get(
        `${WECHAT_SERVICE_CONFIG.wechat.apiBase}/sns/jscode2session`,
        {
          params: {
            appid: WECHAT_SERVICE_CONFIG.wechat.appId,
            secret: WECHAT_SERVICE_CONFIG.wechat.appSecret,
            js_code: code,
            grant_type: 'authorization_code'
          }
        }
      );

      const { openid, session_key } = authResult.data;

      if (!openid) {
        return res.status(401).json({
          error: '认证失败',
          message: '获取用户openid失败'
        });
      }

      // 2. 创建或更新用户信息
      const userData = {
        openid,
        session_key,
        userInfo: userInfo || {},
        lastLogin: new Date()
      };

      // TODO: 这里应该将用户信息保存到数据库
      // const user = await UserModel.findOrCreate(openid, userData);

      // 3. 生成JWT token
      const token = this._generateUserToken(openid);

      res.json({
        success: true,
        token,
        userInfo: {
          openid,
          ...userInfo
        }
      });

    } catch (error) {
      console.error('微信登录失败:', error);
      res.status(500).json({
        error: '登录失败',
        message: error.response?.data?.errmsg || error.message
      });
    }
  }

  /**
   * 解密用户手机号
   */
  async decryptPhoneNumber(req, res) {
    try {
      const { encryptedData, iv, sessionKey } = req.body;

      // 参数验证
      if (!encryptedData || !iv || !sessionKey) {
        return res.status(400).json({
          error: '参数错误',
          message: 'encryptedData、iv和sessionKey不能为空'
        });
      }

      // TODO: 实现手机号解密逻辑
      // 这里需要调用微信的解密算法
      const phoneNumber = await this._decryptWechatData(encryptedData, iv, sessionKey);

      res.json({
        success: true,
        phoneNumber
      });

    } catch (error) {
      console.error('解密手机号失败:', error);
      res.status(500).json({
        error: '解密失败',
        message: error.message
      });
    }
  }

  /**
   * 生成用户token
   * @private
   */
  _generateUserToken(openid) {
    // TODO: 实现JWT token生成逻辑
    return `token_${openid}_${Date.now()}`;
  }

  /**
   * 解密微信数据
   * @private
   */
  async _decryptWechatData(encryptedData, iv, sessionKey) {
    // TODO: 实现微信数据解密算法
    // 这里应该使用crypto模块进行解密
    return '13800138000'; // 示例返回值
  }
}

/**
 * 商品控制器
 */
class ProductController {
  /**
   * 获取商品列表
   */
  async getProducts(req, res) {
    try {
      const { page = 1, limit = 10, category, keyword } = req.query;

      // TODO: 从数据库查询商品列表
      const products = [
        {
          id: 1,
          name: '有机蔬菜套餐',
          price: 28.8,
          category: 'vegetable',
          image: '/images/products/vegetable.jpg',
          farmer: '张大爷',
          location: '北京顺义'
        },
        {
          id: 2,
          name: '农家土鸡蛋',
          price: 15.5,
          category: 'egg',
          image: '/images/products/egg.jpg',
          farmer: '李阿姨',
          location: '河北廊坊'
        }
      ];

      // 过滤逻辑
      let filteredProducts = products;
      if (category) {
        filteredProducts = filteredProducts.filter(p => p.category === category);
      }
      if (keyword) {
        filteredProducts = filteredProducts.filter(p => 
          p.name.includes(keyword) || p.farmer.includes(keyword)
        );
      }

      // 分页
      const startIndex = (page - 1) * limit;
      const paginatedProducts = filteredProducts.slice(startIndex, startIndex + limit);

      res.json({
        success: true,
        data: paginatedProducts,
        pagination: {
          page: parseInt(page),
          limit: parseInt(limit),
          total: filteredProducts.length,
          totalPages: Math.ceil(filteredProducts.length / limit)
        }
      });

    } catch (error) {
      console.error('获取商品列表失败:', error);
      res.status(500).json({
        error: '获取商品失败',
        message: error.message
      });
    }
  }

  /**
   * 创建商品
   */
  async createProduct(req, res) {
    try {
      const productData = req.body;
      const { openid } = req.user; // 从认证中间件获取

      // 参数验证
      if (!productData.name || !productData.price) {
        return res.status(400).json({
          error: '参数错误',
          message: '商品名称和价格不能为空'
        });
      }

      // TODO: 保存商品到数据库
      const newProduct = {
        id: Date.now(),
        ...productData,
        farmerOpenId: openid,
        createTime: new Date(),
        status: 'active'
      };

      res.json({
        success: true,
        data: newProduct,
        message: '商品创建成功'
      });

    } catch (error) {
      console.error('创建商品失败:', error);
      res.status(500).json({
        error: '创建商品失败',
        message: error.message
      });
    }
  }
}

/**
 * 订单控制器
 */
class OrderController {
  /**
   * 创建订单
   */
  async createOrder(req, res) {
    try {
      const orderData = req.body;
      const { openid } = req.user;

      // 参数验证
      if (!orderData.products || !orderData.products.length) {
        return res.status(400).json({
          error: '参数错误',
          message: '订单商品不能为空'
        });
      }

      // TODO: 创建订单逻辑
      const newOrder = {
        orderId: `ORD${Date.now()}`,
        ...orderData,
        openid,
        status: 'pending',
        createTime: new Date(),
        totalAmount: orderData.products.reduce((sum, item) => sum + item.price * item.quantity, 0)
      };

      res.json({
        success: true,
        data: newOrder,
        message: '订单创建成功'
      });

    } catch (error) {
      console.error('创建订单失败:', error);
      res.status(500).json({
        error: '创建订单失败',
        message: error.message
      });
    }
  }

  /**
   * 获取订单列表
   */
  async getOrders(req, res) {
    try {
      const { openid } = req.user;
      const { page = 1, limit = 10, status } = req.query;

      // TODO: 从数据库查询订单
      const orders = [
        {
          orderId: 'ORD123456',
          products: [
            { name: '有机蔬菜套餐', price: 28.8, quantity: 1 }
          ],
          totalAmount: 28.8,
          status: 'completed',
          createTime: new Date('2024-01-15')
        }
      ];

      res.json({
        success: true,
        data: orders,
        pagination: {
          page: parseInt(page),
          limit: parseInt(limit),
          total: orders.length
        }
      });

    } catch (error) {
      console.error('获取订单列表失败:', error);
      res.status(500).json({
        error: '获取订单失败',
        message: error.message
      });
    }
  }
}

// 创建控制器实例
const wechatUserController = new WechatUserController();
const productController = new ProductController();
const orderController = new OrderController();

// 认证中间件
const authMiddleware = (req, res, next) => {
  const token = req.headers.authorization?.replace('Bearer ', '');
  
  if (!token) {
    return res.status(401).json({
      error: '未授权',
      message: '请先登录'
    });
  }

  try {
    // TODO: 验证token并解析用户信息
    // const user = verifyToken(token);
    // req.user = user;
    
    // 临时模拟用户信息
    req.user = { openid: 'mock_openid_123' };
    next();
  } catch (error) {
    return res.status(401).json({
      error: 'token无效',
      message: '请重新登录'
    });
  }
};

// 路由定义

// 用户认证相关路由
router.post('/auth/login', wechatUserController.wechatLogin.bind(wechatUserController));
router.post('/auth/decrypt-phone', wechatUserController.decryptPhoneNumber.bind(wechatUserController));

// 商品相关路由
router.get('/products', productController.getProducts.bind(productController));
router.post('/products', authMiddleware, productController.createProduct.bind(productController));

// 订单相关路由
router.post('/orders', authMiddleware, orderController.createOrder.bind(orderController));
router.get('/orders', authMiddleware, orderController.getOrders.bind(orderController));

// 健康检查
router.get('/health', (req, res) => {
  res.json({
    status: 'ok',
    service: 'wechat-api',
    timestamp: new Date().toISOString()
  });
});

module.exports = router;